You can recalibrate the battery and probably get much more life out of it. MacBook batteries (in fact, all laptop batteries) need to be calibrated every so often, and it’s easy to do. I’ve gotten another hour to hour and a half run time from my MacBook battery after I’ve recalibrated following the instructions below from Apple.
Recalibrating the battery involves charging the battery to 100% and then running your MacBook until it shuts itself down when the battery is exhausted. Then you plug it in and let it charge all the way up. This makes the electronic charging circuits adjust themselves and get used to the way the battery capacity changes over time.
These are the instructions from Apple’s Knowledge Base. (This covers the PowerBook G4 (15-inch Double-Layer SD), MacBook (all models), MacBook Pro (all models), MacBook Pro (17-inch) (all models) and MacBook Air.)
1) Plug in the power adapter and fully charge your PowerBook/MacBook battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged.
2) Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in.
3) Disconnect the power adapter while the computer still on and start running the computer off battery power. You may use your computer during this time. When your battery gets low, the low battery warning dialog appears on the screen.
4) At this point, save your work. Continue to use your computer; when the battery gets very low, the computer will automatically go to sleep.
5) Turn off the computer or allow it to sleep for five hours or more.
6) Connect the power adapter and leave it connected until the battery is fully charged again.
Also, be sure you’ve installed the MacBook battery firmware update, too, if you have the correct MacBook model, as it will help with battery life by getting the battery to charge fully by correcting firmware problems.
If you ever see an “X” in the place of the battery icon in your menu bar, that means your MacBook isn’t recognizing the battery at all (and you’re probably only able to use the MacBook when it’s plugged in) and something more is wrong. Try the battery update above as a first step.
Another thing to try is resetting the resetting the System Management Controller (SMC). Sometimes that will fix the “X” problem, and I’ve found it also helps overall with a battery keeping a good charge. It involves shutting down your MacBook, unplugging it and taking the battery out and then holding down the power key for five seconds. This resets the SMC. Follow the directions in this Apple article.
Yet another thing to try – if resetting the SMC doesn’t seem to help – is reset the PRAM on your MacBook. According to Apple Knowledge Base Article Resetting PRAM and NVRAM
1) Shut down the computer.
2) Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3) Turn on the computer.
4) Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5) Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6) Release the keys.
As a result, your computer’s PRAM and the NVRAM are reset to the default values. The clock settings may be reset to a default date on some models.
If that doesn’t work and you still don’t get much life out of the battery or you still have an “X”, and if your MacBook is under a year old, or under three years old with Applecare Plan, you can try to get a new battery under warranty. Some MacBook batteries have been faulty and Apple has been replacing them. A few years ago I got a new battery for my MacBook after I called Apple and did some over the phone diagnostics with them, and it turned out my battery was within the serial number range of a bad batch.
If you still can’t get much time out of your battery after recalibration, or you have an “X” in the menu bar, start with the Apple support page to see what your options are in terms of warranties and replacements. Or search for and call your local Apple Authorized Service Provider; there are some all over Montana.